diff --git a/mach/powerpc/libem/cms.s b/mach/powerpc/libem/cms.s
index 5bcd3106d..0bcb1ab0b 100644
--- a/mach/powerpc/libem/cms.s
+++ b/mach/powerpc/libem/cms.s
@@ -1,18 +1,17 @@
 .sect .text
 
 ! Compare sets a, b.
-!  Stack: ( b a -- )
-!  With r3 = size of each set
-!  Yields r3 = 0 if equal, nonzero if not equal
+!  Stack: ( b a size -- result )
+!  Result is 0 if equal, nonzero if not equal.
 
 .define .cms
 .cms:
+	lwz	r3, 0(sp)		! r3 = size of each set
 	srwi	r7, r3, 2
 	mtspr	ctr, r7			! ctr = size / 4
-	mr	r4, sp			! r4 = ptr to set a
-	add	r5, sp, r3		! r5 = ptr to set b
+	addi	r4, sp, 4		! r4 = ptr to set a
+	add	r5, r4, r3		! r5 = ptr to set b
 	li	r6, 0			! r6 = index
-	add	r9, r5, r3		! r9 = future sp
 1:
 	lwzx	r7, r4, r6
 	lwzx	r8, r5, r6
@@ -20,10 +19,12 @@
 	addi	r6, r6, 4
 	bne	cr0, 2f			! branch if not equal
 	bdnz	1b			! loop ctr times
-	li	r3, 0			! equal: return 0
+	li	r9, 0			! equal: return 0
 	b	3f
 2:
-	li	r3, 1			! not equal: return 1
+	li	r9, 1			! not equal: return 1
 3:
-	mr	sp, r9			! remove sets from stack
+	slwi	r7, r3, 1
+	add	sp, sp, r7		! adjust stack pointer
+	stw	r9, 0(sp)		! push result
 	blr
diff --git a/mach/powerpc/ncg/table b/mach/powerpc/ncg/table
index 7868f2a3f..84750df05 100644
--- a/mach/powerpc/ncg/table
+++ b/mach/powerpc/ncg/table
@@ -1854,12 +1854,13 @@ PATTERNS
 			cmi INT32
 
 	pat cms defined($1)
-		with STACK
-			kills ALL
-			gen
-				move {CONST, $1}, R3
-				bl {LABEL, ".cms"}
-			yields R3
+		leaving
+			loc $1
+			cal ".cms"
+
+	pat cms !defined($1)
+		leaving
+			cal ".cms"
 
 
 /* Other branching and labelling */